Shock absorbing mechanism



April 12, 1932- E. H. SCHMIDT I SHOCK ABSORBING MECHANISM Filed Jan. 26, 1928 2 sheets-sheet 1 April 12, 1932. E. H. scHMlDT SHOCK ABSORBING MECHANISM Filed Jan. 26, 1928 2 Sheets-Sheet 2 vwwntoz Ernest Hcfzm di @3mi 11i@ @lug/ampia' l Patented Apr. 1 2-, 1932 UNITED STATES iP A'IEIW CFFICEV v ERNEST-ni SCHMIDnoF CLEVELAND HEIGHTS, CHIC, ASSIGNCR ATo NATIONAL MAL LEABLE Ann STEEL CASTINGS COMPANY, onCLnvELAND, oHIo, A conroIaATIon'` f or CHIC y y SHOCK ABSORBING MECHAixTIsn Appii'atiir filed January 26, 192s. seriai'No. 249,521.V

My invention relates to friction shochabsorbing mechanism, and particularly to di aft gear ,of the type shown in my co-pending application,-Serial No. 124,560, filed July 24,

" 1926, in which a-friction barrel or case is'engaged by a plurality of friction shoes and contains means for causing the shoes during compression or release to rotate or have an angular movement relativeto the longitudinal axis y" of the shell, which thereby increasesthe frictional 'resistance and distributes the wear more uniformly withinthe friction casing.

The present. application Vis a continuation in part of the' said application, inso far as I5 the invention relates to providingthewalls of the Yfriction casing with spiral friction grooves andv to forming cooperating-lugs on the shoes in suc-h rnannerthat a'positive ref lease ofthe shoes from the casing is effected.

: Important features of my invention are the location of the spiral friction faces near the center of the shoes; forming the friction case in a rugged beam section so as to transmit "T39 describe and claim.

In'the accompanying drawings Fig. 1 is a plan, partly in section, of a friction draft gear embodying my invention; Figp2is a `sec-` tion on linesIIfII of Fig. 1 ,Fig 3 is a sec- 35 een on lines III-III ofrig. 1; Fig. a is a side elevation, partly in section; Fig.,'5 is a front elevation of the gear; Fig. 6v isa section on lines Vl-VI of Fig. 4; Fig. 7 is a perspective Vof the frictionshell; and Fig. 8 is a perspective of one of thefriction shoes;

lReferring to the drawings, A indicates a spring case or shell'having at its forward end outwardly extending'fianges 2 which are engaged by corresponding flanges 3 on thefrietion 'case B. The flanges 2 and 3 lare held'together by rivets 4. At its rear end the spring case A is provided with wings 5, suitably 'reinforcedwith" the ribs 6, which extend longitudinally of the case and reinforce it against oversolid blows.,

the load through `the heavier sections of the l The friction case B contains friction shoes 8 interposed between the spring seat 9 and the friction wedge 10. The spring case carries one or more draft springs 11, which vbear at one end against the spring seat and at the other end against the base 12 of the spring case. A small release spring 13 may also be interposedbetween the spring seat 9 V'and friction shoes 8. The parts are held in assembled relation by the retaining rod 14,W which has a '60 bearing on the wedge l() and the spring seat 9. The. inside face15 of the friction case B may, if desired, be tapered inwardly toward the rear end, and is preferably provided with grooves 16, the side walls of which form comy pression and release spiral surfaces, indicated, respectively, as 17 and 18. The friction faces 19 ofthe shoes 8 have lugs 2O projecting theref from, the sidewalls 21 and 22 of which incline toward each other, arespiral in form andare l intended, respectively, for cooperation lwith the correspondingly shaped surfaces 17 and The arc-shaped surface 19 of a shoe "8 conforms to and has a frictional'bearing against 75 the inner surface 15 of the friction shell B', while the rear surface 23 of a shoe bears against the forward faceof the lspring seat 9, as isshownin Figsjl and 4. The face 24 may be ofany desired shape. The shoes 8 are Y 80 further provided vwith the wedging surfaces 25 and `26, which engage thecorrespondingly inclined-wedging surfaces 27 and 28 ofthe friction 'wedge 1 v The operation of my improved gear is as 85 follows: When the gear is being compressed,

the friction wedgel() is forced rearwardly `with respect to the friction case Bj, Aand this in turn'moves the shoes rearwardly against the action of the springs 11 andagains't the friction between the'surfac'es 19 of theshoes and the inner facegl of the shell.V As the shoes move rearwardly, thel inclined andspiral compression surfaces 21 of the lugs: 2O onthe shoes cause the yshoes to rotate in oppo-Y site directions, due to the guiding contact of such surfaces 21 with the l'walls 17 inthe grooves 16 of the frictioncase. This causes an additional frictional engagement between Y the'grooves'l -of the case and the faces 21`on f 4serves to equalize the torsional force and eliminates any'tendency of the gear to rotate as a unit. As the pressure abates, the release spring 13, if used, causes a slight outward movement of the wedge and shoes. The' spring or springs 11 then moves the spring seat 9 and with it the'shoes outwardly in a straight line vuntil the surfaces' V18 in the grooves 16.in the caseengage surfaces 22 of the lugs 20. During their vinitialreleasing movement the shoes do not rotate, for the rea son that clearance is provided between the groove 16 and the lug 2O so as to preventl friction and thus provide an easy release. After this initial releasing action has taken place the frictional adhesion between the parts is broken and the spring'll easily restores the parts to their normal position. Y

During release the lugs 2O cause the shoes 8 to rotate in reverse direction and thus to be restored to their initial positions. In the released position as shown the spiral groove surfaces 18 are in contact with the corresponding surfaces 22 of the lugs 20,` and thus provide a -clearance between the compression spiral groove surfaces 17 and the sur-faces 21 on the shoes. This is for Vthe purpose of providing an initial straight-in movement of the shoes, which is `resisted by the spring capacity and to some extent by the friction sur- .faces 15 and 19, but not by the surfacesrof the ribs and grooves, and thus gives a soft preliminary action to the gear. The clearance between one of the shoes and its guiding spiral may be' made greater than that between .the other shoe and itsguiding spiral, with the `result that one shoe may be `caused tofstart iii-rotation ahead of the other both during compression and release, and while the other is still moving in a straight line. This permits the application of a graduated resistance y during compression and a serial release.

The clearance provided between the lugs and the grooves in which they operate is also offfurther advantage in distributing the lines of wear, 'thus giving a somewhat smoother surface than would result from constant travel of the shoes back and forth along the same line.

, Anadvantage in constructing the friction barrel B separate from the spring case A .is Athat they `may be of different material. Thus, for instance, the friction chamber may be made of wear resistant steel and the spring c-ase of malleable iron.

In my improved devicelthe oversoli'd blows .are :transmitted to the base -12 tl11 ughv-tl1e side walls 30 of the spring case. In order to provide the case with greater column strength to resist such blows, the side walls are carried in closely about the springs 11, as at 31. This structure provides a shoulder 32 against which `the spring seat Y9ma-y bear when the gear goes solid. Hence, .oversolid blows are transmitted from the shoulder 32 to the base 12 instead of entirely fromthe forward 4end 3S-'of the spring case A. Inasmuch as the distance from the shoulder 32 to the basev 12 is considerably less thanthe full length of 4the spring case A, oversolid .blows will .therefore be taken partially on the shorter and -therefore stronger column represented by the sectionof ,the spring fcase A which lies `between the shoulder .32 andthe base 12. Further reinforcement is 'gained by the ribs 3A. It will thus be .seen ,that ithe spring case A is of extremely sturdy construction. y

To prevent the side walls ofthe springcase A which are relatively thin because of clearance limitations in the region 35 .as .is shown in Fig. 6, from being damaged by 4oversol'id blows, the friction case Bf'has its :side walls 36 built up soithat the `cylindrical'walls ,86a will merge into side wallsas is best shown in Fig. 7, so `as to yincrease the strength of the friction case and'form it into a .rugged beamsection which will notdelect and which will thus bridge over the `thin side wallsections 35 of .the spring case and carry the loads towardand transmit them through .the heavier sections 87 of `the `spring case, `as is best shown yin Figu.

Matter disclosed but not claimedherein is claimed in my co-pending application, .Se` rial No. 124,560, filed July 244, 1926.

The `terms and expressions which I vhave employed are used .as termsof .description and not of limitation, vand I 4have no inten-- tion, in the use of such terms .and yexpressions of excluding any mechanical .equivalents of the features shownand described, 4or portions thereof, lbut rrecognize .that various structural modifications are possible within the scope ofthe invention claimed.

What I claim is:

1. A shock absorbing mechanism-comprising a friction casing having .spiral .grooves therein; friction shoes; .awedge maintaining the friction 'shoes in frictional engagement with said casing, `said `'shoes .having .spiral ribs thereon cooperating with 'the .spiral grooves in the casing to cause the .shoes to rotate with'respect tothe'weclge-as theymove longitudinally with it .-incompressionof the mechanism, and a compression `spring arranged to oppose the .longitudinal "mo-vement of the shoes.

2. A shock absorbing mechanism-comprising a friction casing having grooves atherein; frictionshoes', a wed-ge maintaining .the .fr-ifct-ion shoes in frictional engagement with .said

Vso

casing, said shoes having ribs thereonfcooperating with the grooves in the casing to cause the shoes to rotate with respect to the wedge as they move longitudinally with it, each of said ribs having a pair of faces one of which engages a spiral face of the groove in compression and the other ofwhich engages the other of the faces of the grooves in release, and a compression spring arranged to oppose the longitudinal movement of the shoes during compression. Y

3. A shock absorbing-mechanism comprising a friction casing-having spiral grooves therein; friction shoes; the casing having circumferential frictionfaces engaged by corresponding arc-shaped faces on the shoes, each shoe havingv upon its arc-shaped face at a distance from the edges thereof a spiral rib cooperating with a corresponding one of the spiral grooves in the casing to rotate the shoes in compression of the mechanism; a wedge for maintaining the friction shoes in frictional engagement with the` casing and for moving them longitudinally relative to it, and a compression spring arranged to oppose the longitudinal movement of the shoes.

4. A shock absorbing mechanism comprising a friction casing having spirall grooves therein; frictionV shoes having spiral ribs thereon, saidpribs and grooves cooperating during buff and draft to cause the shoes and the casing to rotate relative to each other, the said grooves being substantially wider than the ribs to permit the shoes to move longitudinally before being caused to rotate with respect to the casing; a wedge for maintaining the friction shoes in frictionalengagement withthe casing and for moving them longitudinally-relative to it, and a compression spring arranged to oppose the longitudinal movement of the shoes.

5. A shock absorbing mechanism comprising a friction casing having spiral grooves therein, friction shoes having spiral ribs thereon, said ribs and grooves cooperating to cause the shoes and casing under buff and draft to rotate relative to each other, said grooves having sufficient clearance over said ribs to permit the shoes to have an initial 1ongitudinal movement in release to break4 the adhesion of the shoes from the casing; a wedge for maintaining the friction shoes in frictional engagementwith the casing, and a compression spring arranged to oppose the longitudinal movement of the shoes during compression of the mechanism under buff and draft.

6. A shock absorbing mechanism comprising a friction casingy having spiral grooves therein, friction shoes having spiral ribs thereon, said ribs and grooves cooperating to cause the shoes and casing under buE and draft to rotate relative to each other, said grooves having sufficient clearance over saidv ribs to permit the shoes to have an linitial longitudinal' movement incompresslon to givea soft lpreliminaryacti'on to the mechanism; a wedge for maintaining the friction faces during compression of the mechanism, there belng clearance between other sets of faces on said ribs andin said grooves to assist in the positive release of the said frictional engagement as the saidY compression abates, Vanda compression spring arrangedl to oppose the longitudinal` movement of the shoes during compression.

8. A friction, shock absorbing mechanism y comprising a friction ca-sing; friction shoes, the casing having circumferential friction faces engaged by corresponding arc-shaped faces on the shoes, each shoe having adjacent ,its arc-shaped face at a distance fromV the edges thereof a spiral frictionsurface cooperating with a corresponding spiral friction surface on the casing for rotating said shoe in compression of the'mechanism, a wedge for maintainingv the friction shoes in frictional engagement with the casing and for moving them longitudinally relative to it,

andV a compression spring arranged to oppose the llongitudinal movement of the shoes.

Y 9. A friction shock absorbing mechanism comprising a friction casing; friction shoes; Va wedge for maintaining the friction shoes in frictional engagement with said casing; spiral guiding means between the shoes and friction Vcasing for rotating the shoes in opposite directions about the longitudinal aXis of said friction casing during compression of the mechanism, said spiral guiding means comprising av spiral element positioned intermediate the longitudinal edges of each of the friction shoes, and a spring arranged to oppose the longitudinal movement of the shoes during compression.

l0. In a shock absorber structure, a hollow friction member, friction shoe members having frictional engagement with the inner surface of the hollow friction member, a wedging member having telescopic relation to said friction shoe members and arranged under .pressure of the load to force said friction shoe members radially outward to exert pressure against the surfaces of the hollow friction member with which they are in contact, and'interengaging spiral lugs and grooves on the contiguous surfaces of said hollow fric- L11-..30 Y

tion member and said friction shoe members for imparting rotary movement to said shoe members under pressure of the load.

In testimony whereof, I have signed my name to this specification this 21st day of J anuary, 1928.

ERNEST H. SCHMIDT. 

